8.75 posi unit price?

First it isn't called a "posi," because Mopar called it a "suregrip." However, its true name is a "limited slip."

To answer your question it depends on the type you're looking at. A cone type isn't worth as much as a Clutch type. So which Limited Slip unit are you looking to buy, Clutch or Cone (assuming its a factory unit and not an Aftermarket one)?